1. Field of the Invention
The present general inventive concept relates to an audio amp system, and more particularly, to a temperature control apparatus used with an audio amp to prevent the audio amp from overheating and generating noise by effectively controlling a cooling fan of an audio amp system.
2. Description of the Related Art
Commonly, an audio amp amplifies an audio signal to a power signal having a predetermined level. At this time, when an audio output power is high, heat is generated in the audio amp. The heat generated in the audio amp badly affects internal circuits and, in a severe case, may cause a malfunction of the audio amp and a security problem. In an audio system, a cooling fan is used to prevent the audio amp from overheating. However, when the cooling fan operates, considerable noise is generated, and eventually, entire sound quality is deteriorated.
To solve these problems, a cooling fan control strategy for an audio amp in a conventional overheat prevention system is disclosed in U.S. Publication No. 2003/0138115 A1 (U.S. patent application. Ser. No. 10/034,049, filed on Dec. 27, 2001).
FIG. 1 is a block diagram of a conventional temperature control apparatus of an audio amp.
Referring to FIG. 1, a power supply 110 supplies power to a power amp 120 and other blocks. If an audio signal is input to the power amp 120, the power amp 120 operates normally. If a level of the audio signal is maintained high for a predetermined time, an internal temperature of the power amp 120 becomes high.
When the temperature is over a predetermined level, a temperature sensor 130 attached to the power amp 120 transmits an overheating signal to a micro controller 140 or a cooling fan driver 150.
The micro controller 140 or the cooling fan driver 150 drives a cooling fan 160 to prevent the audio amp from overheating. When the cooling fan 160 operates, air ventilates an inside of the audio amp, the internal temperature of the power amp 120 becomes low, and the overheating is prevented.
However, a process of the temperature sensor 130 to detect the overheating of the power amp 120 and transmit the overheating signal to the micro controller 140 is too slow and not precise. Also, when the temperature sensor 130 transmits the overheating signal to the micro controller 140, the audio amp 120 has already malfunctioned or sound quality has dramatically been deteriorated due to distortion of output signals of the audio amp 120.
Besides the overheat prevention system of the audio amp shown in FIG. 1, there is a cooling fan control method using a level of a volume. In this method, a cooling fan always rotates whenever the level of the volume is high even if speakers are not connected to an audio amp. However, since overheating is not generated no matter how high the volume may be if the speakers are not connected to the audio amp, it is unnecessary to operate the cooling fan. Also, even though the speakers are connected to the audio amp, since the generated heat capacity varies according to the number of connected speakers, it is difficult to precisely control the cooling fan.